A numerical study of the flow in the wake of a plate of finite thickness

1999 ◽  
Vol 10 (2) ◽  
pp. 151-159
Author(s):  
K. B. Murashkin ◽  
V. M. Paskonov ◽  
S. V. Fortova
Keyword(s):  
Numerical Study ◽  
Finite Thickness

The shear strength of soils containing undulating shear zones—a numerical study

1988 ◽  
Vol 25 (3) ◽  
pp. 550-558 ◽  
Author(s):  
George T. Dounias ◽  
David M. Potts ◽  
Peter R. Vaughan
Keyword(s):  
Strain Softening ◽  
Numerical Study ◽  
Finite Thickness ◽  
Shear Zones ◽  
Shear Surface ◽  
Weak Zone ◽  
Surface Finite Elements ◽  
Soil Block ◽  
Strength And Deformation ◽  
Intact Soil

This paper investigates the behaviour of a clay layer containing an undulating shear surface, when sheared across the undulations. A relatively long soil block containing an undulating weak zone of finite thickness is assumed. A finite element study is undertaken, examining the effect of the thickness and the amplitude of the weak zone on the overall strength and deformation of the block. Also examined is the behaviour of the block when either only the weak zone or both the weak zone and the intact soil are strain softening. Key words: undulating shear surface, finite elements, strain softening.

Natural Convection in a Partitioned Vertical Enclosure Heated With a Uniform Heat Flux

2006 ◽  
Vol 129 (6) ◽  
pp. 717-726 ◽  
Author(s):  
Kamil Kahveci
Keyword(s):  
Heat Flux ◽  
Nusselt Number ◽  
Natural Convection ◽  
Thermal Resistance ◽  
Average Nusselt Number ◽  
Numerical Study ◽  
Finite Thickness ◽  
Vertical Wall ◽  
Uniform Heat Flux ◽  
Uniform Heat

This numerical study looks at laminar natural convection in an enclosure divided by a partition with a finite thickness and conductivity. The enclosure is assumed to be heated using a uniform heat flux on a vertical wall, and cooled to a constant temperature on the opposite wall. The governing equations in the vorticity-stream function formulation are solved by employing a polynomial-based differential quadrature method. The results show that the presence of a vertical partition has a considerable effect on the circulation intensity, and therefore, the heat transfer characteristics across the enclosure. The average Nusselt number decreases with an increase of the distance between the hot wall and the partition. With a decrease in the thermal resistance of the partition, the average Nusselt number shows an increasing trend and a peak point is detected. If the thermal resistance of the partition further declines, the average Nusselt number begins to decrease asymptotically to a constant value. The partition thickness has little effect on the average Nusselt number.

A Numerical Study of Natural Convective Heat Transfer From Two-Sided Inclined Square Plates Having a Finite Thickness

2019 ◽  
Author(s):  
Rafiq Manna ◽  
Patrick H. Oosthuizen
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Numerical Study ◽  
Finite Thickness ◽  
Plate Thickness ◽  
Side Surface ◽  
Bottom Surface ◽  
Study Results ◽  
Inclination Angles

Abstract Simultaneous natural convective heat transfer from the top, bottom and side surfaces of two-sided inclined square plates having various thicknesses has been numerically investigated. The aim of this work is to determine whether the plate thickness has a significant influence on the heat transfer rates from the plate surfaces when the plate is inclined to the horizontal and to determine how the heat transfer rate varies with this angle of inclination. The upper, lower and side surfaces of the plate have been assumed to be isothermal and at the same temperature which is higher than that of the surrounding fluid. The range of conditions considered is such that laminar, transitional, and turbulent flow occur over the plate. The numerical solution has been obtained using the commercial CFD solver ANSYS FLUENT©. In this study, results have only been obtained for the case where the plate is exposed to air. Inclination angles of between 0 and 40 degrees from the horizontal and plate dimensionless thicknesses (thickness-to-side length ratios) of between 0 and 0.3 have been considered. Variations of the mean Nusselt number with Rayleigh number for the top surface, bottom surface, side surface and that averaged over all heated surfaces of the plate for various inclination angles and for various plate dimensionless thicknesses have been obtained.

Liquid Film Evaporation in the Presence of Micro Encapsulated Phase Change Materials: A Numerical Study

2013 ◽  
Author(s):  
Yasmin Khakpour ◽  
Jamal Seyed-Yagoobi
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Phase Change ◽  
Phase Change Materials ◽  
Numerical Study ◽  
Finite Thickness ◽  
Operating Conditions ◽  
Evaporation Process ◽  
Constant Wall Temperature ◽  
Film Evaporation

This paper numerically investigates the flow and heat transfer characteristics of a slurry of micro encapsulated phase change materials (MEPCM) and R134a in the presence of film evaporation. The numerical domain is comprised of a minichannel in contact with a finite thickness solid zone with constant wall temperature. During the evaporation process, the concentration of MEPCM in the slurry increases, resulting in a continuous variation of effective thermal properties of the slurry. The effect of PCM concentration on the evolution of the liquid film thickness under different operating conditions along with the variation of the local heat transfer coefficients has been studied. A user defined function has been developed to incorporate the evaporation process by introducing the mass and energy source terms for the evaporation process as well as the variation of the MEPCM concentration along the channel.

Numerical Study of Heat Transfer Characteristics of Liquid Flow in a Microtube With Blend of Micro Phase Change Materials

2012 ◽  
Author(s):  
Yasmin Khakpour ◽  
Jamal Seyed Yagoobi
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Liquid Flow ◽  
Phase Change Materials ◽  
Numerical Study ◽  
Finite Thickness ◽  
Local Heat Transfer ◽  
Outer Wall ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

This numerical investigation explores the heat transfer characteristics of liquid flow with two-component (blend) micro phase change materials (MPCM) and compares them with those of a single component MPCM slurry. The numerical domain is comprised of an axisymmetric micro-tube in contact with a finite-thickness solid zone and a constant heat flux applied on the solid outer wall. The ultimate objective is to demonstrate the tunability of PCM fluid’s thermal energy properties when the phase transition temperatures of the PCMs are chosen within a range required for a specific application. This is because different pure PCM materials store latent heat at a specific range of temperatures. The MPCM slurry flow does not reach a fully developed condition as long as the MPCM particles experience phase change in the developing region. The local heat transfer coefficient strongly depends on the corresponding location of the melting zone interface.

Influence of moving plate velocity on conjugate heat transfer due to the impingement of an inclined slot jet

2019 ◽  
Vol 30 (12) ◽  
pp. 2050006 ◽  
Author(s):  
Shashikant Pawar ◽  
Devendra Kumar Patel
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Coefficient ◽  
Skin Friction ◽  
Numerical Study ◽  
Finite Thickness ◽  
Skin Friction Coefficient ◽  
Moving Plate ◽  
Potential Core ◽  
Plate Velocity

In this paper, a dimensionless numerical study of the flow-field and heat transfer characteristics of an incompressible turbulent slot jet impinging obliquely over a moving surface of finite thickness is presented. Simulations were performed using [Formula: see text] eddy viscosity turbulence model. The temperature field was solved simultaneously in the solid and the fluid domain. For a fixed impingement distance and a fixed Reynolds number, the impingement angle ([Formula: see text]) and plate velocity ([Formula: see text]) were varied in the range of 30–75∘ and 0–0.3, respectively. In the results, the length of the potential core depends on the jet inclination, which increases with increase in jet angle. The jet angle and plate velocity have more influence on the uphill side compared to the downhill side. The location of stagnation displaces toward the uphill side as the inclination angle decreases, and the drifting of stagnation point is noted with the variation in plate velocity. The average skin-friction coefficient increases with increase in [Formula: see text] and [Formula: see text], and the influence of [Formula: see text] on the skin-friction coefficient is reduced as [Formula: see text] increases. The maximum Nusselt number ([Formula: see text]) increases with increase in [Formula: see text], and the drifting of [Formula: see text] is observed with increase in plate velocity. It is found that the average Nusselt number increases quickly with increase in plate velocity for lower angles of impingement. The distribution of local heat flux follows the same trend as the local Nusselt number.

A Numerical Study of Natural Convection in Partially Open Enclosures With a Conducting Side-Wall

2004 ◽  
Vol 126 (1) ◽  
pp. 76-83 ◽  
Author(s):  
G. Desrayaud ◽  
G. Lauriat
Keyword(s):  
Natural Convection ◽  
Numerical Study ◽  
Finite Thickness ◽  
Vertical Wall ◽  
Side Wall ◽  
Practical Applications ◽  
Hot Air ◽  
Aspect Ratios ◽  
Vertical Walls ◽  
Rayleigh Numbers

A numerical study of natural convection generated by a cold vertical wall of an enclosure with two openings on the opposite wall of finite thickness is presented. The enclosure is connected to an infinite reservoir filled with hot air. A two-dimensional laminar flow is assumed both within the enclosure and along the side of the bounding wall immersed into the reservoir. The effects of the size of the openings, spacing between the vertical walls and thermal resistance of the bounding wall are investigated. Numerical results are discussed for aspect ratios of the enclosure and Rayleigh numbers relevant to practical applications.

Numerical Study on Conjugate Conduction–Convection in a Cubic Enclosure Submitted to Time-Periodic Sidewall Temperature

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Wei Zhang ◽  
Zhu Huang ◽  
Chuhua Zhang ◽  
Guang Xi
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Wall Thickness ◽  
Numerical Study ◽  
Finite Thickness ◽  
Pseudospectral Method ◽  
Thermal Conductivity Ratio ◽  
Conjugate Conduction ◽  
Time Periodic ◽  
Diffusivity Ratio

The laminar conjugate conduction-natural convection heat transfer in a cubic enclosure of finite thickness conductive walls and central cavity filled with fluid is comprehensively studied by using recently developed high accuracy temporal-spatial multidomain pseudospectral method. The enclosure is assumed to have one sidewall submitted to time-periodic pulsating temperature and the opposing sidewall constant temperature, and the top, bottom and two lateral sidewalls are adiabatic. The present study is devoted to explore the fluid mechanics and heat transfer mechanisms of the time-periodic conjugate conduction-natural convection in the enclosure, with particular highlights on the heat transfer resonance and back heat transfer phenomena, the perturbation propagation patterns and the three-dimensional characteristics. The computations are performed for wide ranges of controlling parameters of engineering significance, i.e., the dimensionless wall thickness 0 ≤ s ≤ 0.10, the solid–fluid thermal conductivity ratio 10 ≤ k ≤ 50 and diffusivity ratio 0.001 ≤ a ≤ 0.1, and the sidewall temperature pulsating period 1 ≤ P ≤ 103. Numerical results reveal that the time-periodic fluid flow and conjugate heat transfer performances of the enclosure system are greatly affected by the conductive walls and complexly dependent on the controlling parameters. The thickness and thermophysical properties of the conductive walls, together with the pulsating period of the sidewall temperature, govern the sidewall temperature disturbance propagation patterns (amplitude, phase position and speed) within the enclosure. The heat transfer resonance only appears in cases of large diffusivity ratio, but the variation of period-averaged heat transfer rate with respect to the pulsating period is quite different from that of the zero wall thickness enclosure. The back heat transfer exists in region close to the corners formed by either the top or bottom walls and the enclosure hot sidewall, and the former is more remarkable in both scale and duration and is gradually disappearing as the pulsating period increases.

scholarly journals Shock interaction with a heavy gas cylinder: Emergence of vortex bilayers and vortex-accelerated baroclinic circulation generation

2003 ◽  
Vol 21 (3) ◽  
pp. 443-448 ◽  
Author(s):  
SANDEEP GUPTA ◽  
SHUANG ZHANG ◽  
NORMAN J. ZABUSKY
Keyword(s):  
Numerical Study ◽  
Finite Thickness ◽  
Weak Shock ◽  
Incident Shock ◽  
Incident Shock Wave ◽  
Gas Cylinder ◽  
Baroclinic Circulation ◽  
Strong Gradient ◽  
Heavy Gas ◽  
Piecewise Parabolic

We present a numerical study to late times of a Richtmyer–Meshkov environment: a weak shock (M= 1.095) interacting with a heavy cylindrical bubble. The bubble interface is modeled as a diffuse interfacial transition layer (ITL) with finite thickness. Our simulation with the piecewise parabolic method (PPM) yields very good agreement in large- and intermediate-scale features with Jacobs' experiment (Jacobs, 1993). We note the primary circulation enhancement deposited baroclinically upon the incident shock wave, and significant secondary baroclinic circulation enhancement, first observed in Zabusky and Zhang (2002). We propose that this vortex-accelerated circulation deposition is universal. These baroclinic processes are mediated by a strong gradient intensification and stretching of the ITL and result in close-lying vortex bilayers (VBLs) and the emergence of vortex projectiles (VPs). These account for the elongated, kidney-shaped morphology of the rolled up bubble domain at late times.

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